Abstract: The envelope incorporates a pair of sheet materials secured one to another to form a pocket enclosure. Each sheet is comprised of a plastic (e.g. polyethylene) film on one side and a fabric (e.g. polyester) layer on the other side. The two sheets are secured by heat sealing with the plastic sides facing one another and the pocket is dimensioned to accept an available x-ray cassette. In use, the fabric layer of the envelope represents the side that is in contact with the patient being examined.